POLAR MODULATION TRANSMISSION APPARATUS

• US 20100029224A1
• Filed: 08/04/2009
• Published: 02/04/2010
• Est. Priority Date: 08/04/2008
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: URUSHIHARA, Tomoya, Matsuoka, Akihiko
• Granted Patent: US 8,135,361 B2
• Time in Patent Office: Days
• US Class Current: 455/102
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/0483 Transmitters with multiple parallel paths
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control

Abstract

By compensating for a detection result of the detector in feedback control of output power of the power amplifier, the polar modulation transmission apparatus is able to realize accurate transmission power control. Polar modulation transmission apparatus 100 has detector 106 that detects output power of power amplifier 103, PAPR calculating section 131 that calculates the PAPR of the spread modulated signal, compensation value generating section 134 that outputs a compensation value corresponding to the calculated PAPR and an arithmetic operator that performs an arithmetic operation using the compensation value and a detection result obtained by detector 106. By this means, it is possible to compensate for the sensitivity of detector 106 (measurement sensitivity) that changes depending on the P parameter and mode and make the sensitivity of detector 106 (measurement sensitivity) virtually constant.

Claims

1. A polar modulation transmission apparatus that inputs a phase modulated signal which is generated using a phase component of an input signal, to a signal input port of a power amplifier, and that inputs a power supply voltage, which is adjusted using an amplitude component of the input signal, to a power supply input port of the power amplifier, the polar modulation transmission apparatus comprising:

a detector that detects an output power of the power amplifier;

a PAPR (Peak to Average Power Ratio) calculating section that calculates PAPR of the input signal;

a compensation value generating section that generates a compensation value corresponding to the PAPR calculated in the PAPR calculating section; and

a transmission power control section that performs an arithmetic operation of a detection result obtained in the detector, using the compensation value, and that, by scaling each of the phase modulated signal and the power supply voltage based on an arithmetic operation result obtained by the arithmetic operation, controls the output power of the power amplifier.

2. The polar modulation transmission apparatus according to claim 1, further comprising a data channel detecting section that detects whether or not a data channel signal is included in the input signal,

wherein the compensation value generating section generates a sensitivity compensation value as the compensation value for compensating for detection sensitivity of the detector, and

generates a first sensitivity compensation value when the data channel detecting section decides that the data channel signal is included in the input signal, andgenerates a second sensitivity compensation value different from the first sensitivity compensation value when the data channel detecting section decides that the data channel signal is not included in the input signal.

3. The polar modulation transmission apparatus according to claim 2, wherein:

the input signal comprises a complex signal; and

the data channel detecting section decides whether or not the data channel signal is included in the input signal based on a signal point constellation of the input signal.

4. The polar modulation transmission apparatus according to claim 2, wherein, when an absolute value of an in-phase component and an absolute value of a quadrature component of the input signal are equal, the data channel detecting section decides that the data channel signal is not included.

5. The polar modulation transmission apparatus according to claim 1, further comprising a data channel detecting section that detects a scale of a data channel signal included in the input signal,

wherein the compensation value generating section generates a varying compensation value depending on the scale of the data channel signal detected in the data cannel detecting section.

6. The polar modulation transmission apparatus according to claim 5, wherein the data channel detecting section detects the scale of the data channel signal by calculating a difference between an absolute value of an in-phase component and an absolute value of a quadrature component of the input signal.

7. The polar modulation transmission apparatus according to claim 1, wherein:

the data channel detecting section detects a scale of a data channel signal by calculating a difference between an absolute value of an in-phase component and an absolute value of a quadrature component of the input signal; and

the compensation value generating section generates a sensitivity compensation value as the compensation value for compensating for detection sensitivity of the detector, and

(1) generates a first sensitivity compensation value when the data channel detecting section decides that the difference between the absolute value of the in-phase component and the absolute value of the quadrature component of the input signal is zero,

(2) generates a second sensitivity compensation value different from the first sensitivity compensation value when the data channel detecting section decides that the difference between the absolute value of the in-phase component and the absolute value of the quadrature component of the input signal is greater than zero and less than a predetermined threshold, and

(3) generates a third sensitivity compensation value different from the first sensitivity compensation value and the second sensitivity compensation value when the data channel detecting section decides that the difference between the absolute value of the in-phase component and the absolute value of the quadrature component of the input signal is equal to or greater than the predetermined threshold.

8. The polar modulation transmission apparatus according to claim 1, wherein the transmission power control section comprises a multiplying section that multiplies the compensation value by a detection result obtained in the detector.

9. The polar modulation transmission apparatus according to claim 1, wherein, as the compensation value, the compensation value generating section stores sensitivity compensation values for compensating for detection sensitivity of the detector in association with values of PAPR.

10. The polar modulation transmission apparatus according to claim 1, wherein the transmission power control section comprises an adding section that adds the compensation value to a detection result obtained in the detector.

11. The polar modulation transmission apparatus according to claim 1, wherein, as the compensation value, the compensation value generating section stores, in association with values of PAPR, inter-mode compensation values for making smaller a difference between a value detected in the detector in compressed mode and a value detected in the detector in uncompressed mode.

12. The polar modulation transmission apparatus according to claim 11, further comprising a data channel detecting section that detects whether or not a data channel signal is included in the input signal,

wherein the compensation value generating section

(1) generates a first inter-mode compensation value when the data channel detecting section decides that the data channel signal is included in the input signal, and

(2) generates a second inter-mode compensation value different from the first inter-mode compensation value when the data channel detecting section decides that the data channel signal is not included in the input signal.

13. The polar modulation transmission apparatus according to claim. 12, wherein:

the input signal comprises a complex signal; and

the data channel detecting section decides whether or not the data channel signal is included in the input signal, based on a signal point constellation of the input signal.

14. The polar modulation transmission apparatus according to claim 12, wherein, when an absolute value of an in-phase component and an absolute value of a quadrature component of the input signal are equal, the data channel detecting section decides that the data channel signal is not included.

15. The polar modulation transmission apparatus according to claim 11, further comprising a data channel detecting section that detects a scale of a data channel signal included in the input signal,

wherein the compensation value generating section generates a varying inter-mode compensation value depending on the scale of the data channel signal detected in the data cannel detecting section.

16. The polar modulation transmission apparatus according to claim 15, wherein the data channel detecting section detects the scale of the data channel signal by calculating a difference between an absolute value of an in-phase component and an absolute value of a quadrature component of the input signal.

17. The polar modulation transmission apparatus according to claim 11, wherein:

the data channel detecting section detects a scale of a data channel signal by calculating a difference between an absolute value of an in-phase component and an absolute value of a quadrature component of the input signal; and

the compensation value generating section

(1) generates a first inter-mode compensation value when the data channel detecting section decides that the difference between the absolute value of the in-phase component and the absolute value of the quadrature component of the input signal is zero,

(2) generates a second inter-mode compensation value different from the first inter-mode compensation value when the data channel detecting section decides that the difference between the absolute value of the in-phase component and the absolute value of the quadrature component of the input signal is greater than zero and less than a predetermined threshold, and

(3) generates a third inter-mode compensation value different from the first inter-mode compensation value and the second inter-mode when the data channel detecting section decides that the difference between the absolute value of the in-phase component and the absolute value of the quadrature component of the input signal is equal to or greater than the predetermined threshold.

18. The polar modulation transmission apparatus according to claim 17 wherein:

the transmission power control section comprises;

a power table that stores a power setting value; and

a power setting module that compensates for a read address of when a power setting value is read from the power table; and

the power setting module performs an arithmetic operation using the compensation value outputted from the compensation value generating section and the read address.

19. The polar modulation transmission apparatus according to claim 1, wherein the transmission power control section generates a first scaling coefficient for scaling the phase modulated signal and a second scaling coefficient for scaling the power supply voltage.

20. The polar modulation transmission apparatus according to claim 1, wherein the input signal comprises a spread modulated signal.